prefer avio_check() over url_exist()

The problem with url_exist() is that it tries to open a resource in
RDONLY mode. If the file is a FIFO and there is already a reading
client, the open() call will hang.

By using avio_check() with access mode of 0, the second reading
process will check if the file exists without attempting to open it,
thus avoiding the lock.

Fix issue #1663.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/ffmpeg.c b/ffmpeg.c
index 5b6e3eae67..6e620bf55e 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -3733,7 +3733,7 @@ static void opt_output_file(const char *filename)
             (strchr(filename, ':') == NULL ||
              filename[1] == ':' ||
              av_strstart(filename, "file:", NULL))) {
-            if (url_exist(filename)) {
+            if (avio_check(filename, 0) == 0) {
                 if (!using_stdin) {
                     fprintf(stderr,"File '%s' already exists. Overwrite ? [y/N] ", filename);
                     fflush(stderr);